Where’s the evidence for gluten sensitivity?

Recently I have noticed a huge increase in the use of the term gluten sensitivity, which is alleged to cause non-specific and usually mild gastrointestinal symptoms. Abdominal pain and discomfort, dyspepsia, bloating, and meteorism are symptoms commonly attributed to functional disorders of the gastrointestinal tract (irritable bowel syndrome, or IBS). Dietary change is well known to provide benefits in irritable bowel syndrome,1 and the condition sometimes responds well to a gluten-free diet. This is despite the absence of the histology and serology typical of coeliac disease—duodenal villous atrophy, intraepithelial lymphocytosis, crypt hyperplasia, and the presence of anti-transglutaminase type 2 IgA antibodies in sera. Genetically, coeliac disease and gluten sensitivity partially share the same susceptibility, although the HLA-DQ2/DQ8 haplotype is not necessary to develop gluten sensitivity.2

Gluten sensitivity implies gastrointestinal or extraintestinal symptoms that respond to …